Orthopedic inlay for footwear



May 31, 1966 w` M. scHoLL 3,253,600

ORTHOPEDIC INLAY FOR FOOTWEAR Filed Sept. 6, 1963 NE YS United States Patent O 3,253,600 ORTHOPEDIC INLAY FOR FOOTWEAR William M. Scholl, 213 W. Schiller St., Chicago, lll. Filed Sept. 6, 1963, Ser. No. 307,253 4 Claims. (Cl. 12S-582) Ths invention relates to improvements in an orthopedic inlay for orthopedic shoes, and more particularly to an inlay of substantial thickness utilized in a-shoe constructed to allow extraspace and depth for the accommodation of the inlay, leaving sufficient room for the foot to be comfortably fitted as in a standard measurement shoe, the inlay being highly desirable for use in post-operative shoes for cases of hallux valgus, hammer toe, flexus, foot and ankle edemas, arthritic or diabetic conditions, and other atiiictions, as will be apparent to one skilled in the art.

In the past, various types of inlays for orthopedic shoes have been developed, but in practically every instance such inlays embodied a moldable composition which had to be molded to the individual foot of the user and which then took a permanent set, so that in most cases a minimum cushioning property remained and if any adjustments had to be made at a later date, the inlay was ground, carved, or otherwise shaped by mechanical means. Such procedure, while highly desirable for extremely deformed or partially amputated feet, was often so expensive that -the patient frequently neglected to purchase new shoes or have a new inlay made for too long a time for proper treatment. This was particularly true in regard to those patients having lesser afflictions where an orthopedic inlay was still indicated. Further, molded inlays of the character utilized heretofore necessitate several visits to the shoe or foot specialist by the patient.

With thevforegoing in mind, it is an important object of the instant invention to provide a preformed orthopedic inlay for footwear embodying material that is selfconforming to a particular foot when pressure is applied to the material, and which material has a low recovery factor so that it retains the shape to which it is conformed for a relatively long period of time after pressure on the inlay is removed.

Another important object of this invention is the provision of a preformed orthopedic inlay for disposition in an article of footwear and `of such character that a patient or customer may purchase an article of footwear having vthe orthopedic inlay therein, and limmediately wear the article of footwear, the inlay automatically and without further aid conforming itself to the shape of the plantar surface of the particular foot.

It is also a feature of this invention to provide an orthopedic inlay for au article of footwear, which inlay embodies foam cushioning material which automatically `conforms itself to a contour in keeping with the plantar surface of a particular foot as accurately as though it were molded with that particular foot as a pattern, and yet retains its foot cushioning property.

A further feature of this invention is the provision of an orthopedic inlay for an article of footwear which inlay includes a base, self-conforming slow recovering cushioning material on that base, and means to prevent lateral migration of the cushioning material.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawing, in which:

FIGURE l is a cutaway view of an article of footwear showing an inlay embodying principles of the instant invention in operative position therein;

FIGURE 2 is a plan view of the inlay itself removed from the shoe and indicating a contoured formation on the inlay;

-equivalent material usedas a binder.

Patented May 31, 1966 ice FIGURE 3 is a longitudinal vertical sectional view through the inlay;

FIGURE 4 is a transverse vertical sectional view taken substantially as indicatedby the line IV-IV of FIGURE 2, looking in the direction of the arrows; and

FIGURE 5 is a fragmentary greatly magnified diagrammatic view illustrating the action of the cushioning material embodied in the inlay.

As shown on the drawings I In FIGURE l, I have illustrated an article of footwear, in the form of an Oxford-type shoe, in which an inlay, generally indicated by numeral 2, is disposed in operative position. The shoe 1 is preferably made over a last so shaped or built up as to provide extra space and depth to accommodate the inlay so as to provide a feeling to the customer the same as that of a standard shoe ofthe proper size. y

With reference more particularly to FIGURE 3, it will be seen that the inlay comprises a base member 3 which is preferably molded in one piece of any suitable material, and a satisfactory substance for this purpose is mainly cork. The inlay may satisfactorily be made of compressed ground cork with cement, latex, plastic, or

The base, therefore, possesses some resiliency, and instead of being rigid and hard, willyield to some extent to pressure thereupon.

The upper surface of the base member 3 is preferably contoured in keeping with the plantar surface of -a normal foot. To that end, the base member 3 varies in thickness so as to provide a hollow arcuate heel seat 4, an elevation 5 under the longitudinal arch of the foot, which elevation is higher on the inner side of the inlay than it is on the outer side in keeping with the longitudinal arch of the foot, and as indicated at 6 in FIGURE 4. The

base member is also provided with an elevation 7 as seen in FIGURE 4 to underlie the metatarsal arch of the foot, such elevation being preferably sized so as to underlie the three intermediate metatarsal heads. Such shaping of the base member provides a generally fundamentally correct upper surface contour for the entire inlay, in keeping with the contour of a normal foot.

Disposed over the Iupper `face of the base member 3 is a sheet 8 of foam cushioning material, preferably of substantially uniform thickness throughout, a thickness of Y 1/8 or 5716 inch being satisfactory in most cases. The sheet 8 is preferably attached to -the upper face of the base member 3 by la thin light cement.

yOver the top of `the cushion layer 8 is a thin smooth surfaced cover 9 which may be of leather, imitation leather, plastic `film, or any other suitable material. This cover has its bounding margin 10 turned down over the bounding edge or side of the base member G to which it is firmly cemented. The lcover might also be attached with a thin light cement to the top surface of the cushioning layer 8, if so desired. However, the cementing of the cover to the base member 3 around the side edge thereof maintains the cushion layer 8 in proper position against lateral migration `over the edge of the base member under foot pressure.

Both the cushion sheet and the cover 9, as clearly seen in FIGURES 3 and 4 conform to the contoured upper face of the base member 3 so that at the very outset the foot rests upon a properly shaped surface. In accordance with the instant invention, however, it is desired that the inlay be in conformity with a foot that is not normal, but which may have-heavy calluses, projections, excrescences, somewhat `flattened arches, or other such deformities or aiictions.

To that end, it is desired that the sheet 8 be of a selfconforming material which automatically and almost immediately assumes a shape complemental to the plantar surface of a particular foot, conforming to any projection, excrescence, or other variance from a normal foot that might appear on that particular foot. It is also desired that the material of the sheet 8 assumes at least a partial set and recover very slowly from that partial set when pressure is removed. By partial set is meant a material that will conform to the plantar surface of a particular foot and retain its conformed shape for a relatively long interval of time following the removal of the foot pressure.

While various materials might be suitable for such usage, plastic foams are at the present time deemed preferable, such as vinyl foams, polyester or isocyanate foams, polyurethane foams, and the like. By way of example and not by way of limitation, I may mention that one ma- 'terial that has proven highly satisfactory in practice and under tests is `a homopolymer polyvinyl chloride foam.

Such foam may be had with open cells'or closed cells.

`With open cells, however, only approximately a set from which slow recovery is had may be obtained, while with closed cells a 50% set may be obtained because of the exclusion of air. Accordingly it is preferable to ut-ilize such a foam with closed cells in the range of 70% to 100%. The foam is fully cured, substantially air impervious and non-porous. These advantages lare enhanced by providing a thin skin on both sides of the foam which not only adds to the strength of the foam layer, but Ialso enhances slow recovery, because it seals out air. That skin may be provided by controlling the density and expansion of the foam at 'the time it is made. The foam is not split but is cast on a suitable substrate at the desired thickness.

Compression tests have been run on such foam for 22 Vhours at 15 8 lF. under a load sufficient to reduce the foam `ery for the two-hour period was found to be approximately 58%. At normal room temperature the recovery would be even slower, but t-he cushioning effect of the ma- .terial upon the foot is always present since there is always some recovery.

In FIGURE 5 1I have diagrammatically illustrated the action of the foam under pressure. As indicated in this ffigure, the skin would be along the surface 11 and along the surface 12. Assuming the right-hand portion of the -(ligure as generally indicated by numeral 13 to be the thickness of the foam before usage with the `closed gas filled cells generally globular, an impression may be caused in the foam by foot pressure as generally indicated by numeral 14 and the closed cells flattened out, and since air is substantially excluded, the recovery of the foam from vsuch compressed condition 14 will be very slow.

When in use, the inlay immediately conforms itself to the contour of the plantar surface of a particular foot, as indicated by the heavily shaded portion 15 in FIGURE 2.

.Wherever there is a protuberance, excrescence, or some similar affliction there will be a corresponding depression vin the inlay, in excess of that caused yby the contact of a normal foot. lIt will also be noticed that there will be little if any compression of the inlay in the region 16 provided the inner longitudinal arch is well elevated, and

there will also be a rise in the material as indicated at `17 between the depressions caused by the toes and the fleshy parts of the foot in the metatarsal arch region. This elevation 17 will be under the sulci of the toes to comfortably dit beneath the toes and at-the same time the toes will tend to grip that elevation during `walking and beneficial exercise to the foot results.

Should a particular foot indicate the need for additional paddings or other corrections, the inlay is easily removed for purposes of building it up at specified points, cutting sections of it away if necessary, grinding the cork base 3 to lessen its thickness at certain locations, and similar adjustments. i

After the inlay has been used a short time, and assuming that it is used regularly, the foam layer 8 will retain at least a portion of the foot impression overnight, so that with regular usage there will always be at least al partial impression present at the start of the d ay. Overnight is not a sufiicient length of time -for full recovery ofthe material in the event it is in daily use.

From the foregoing, it is apparent that I have provided an orthopedic inlay for articles of footwear which almost immediately conforms itself to a contour in keeping with the plantar surface of an individual foot, aids in provid- `ing beneficial exercise for the yfoot while in use, and retains its cushioning properties throughout even though the recovery factor is relatively low. Futhermore the inlay is simple in construction, economical to make and economical to use since in many cases no adjustment is necessary and the user may purchase the article of footwear with the inlay therein at one visit to the foot specialist and acquire immediate relief.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. An orthopedic inlay for footwear comprising:

a base having a top surface contoured in keeping with the plantar surface of a normal foot, and a layer of substantial thickness of thermoplastic foam cushioning material having to 100% gas-filled closed cells throughout and an outer impervious skin,

said layer conforming under foot pressure to the surface of a foot and being possessed of a low recovery factor of less than 70% in a two-hour interval after removal of foot pressure.

2. An orthopedic inlay as defined in claim 1, in which said layer of thermoplastic foam comprises a fully cured homopolymer polyvinyl chloride foam.

3. An orthopedic inlay as defined in claim 1, in which said foam layer includes a ridge under the sulci of the toes to exercise .the foot during walking.

4. An orthopedic inlay as defined in claim 1, including, in addition, a smooth thin cover over said foam layer having a downwardly turned margin secured to an outwardly facing bounding edge of said base to prevent lateral migration of said foam layer under foot pressure.

References Cited by the Examiner UNITED STATES PATENTS 2,288,686 7/1942 Daniels 128--595 X 2,546,827 3/1951 Lavinthal 128-595 2,626,886 1/1953 Scholl 12S-595 X 2,760,281 18/ 1956 Cosin 128-595 2,961,780 1l/1960 McManus 128--586 3,121,430 2/ 1964 OReilly 128--595 3,135,265 6 /1964 Holzman 12S-619 References Cited by the Applicant UNITED STATES PATENTS 2,504,704 4/ 1950 Lee. 2,878,153 3/ 1959 Hacklander. 2,878,593 3/1959 Lockridge. 2,953,130 9/ 1960 Scholl.

RICHARD A. GAUDET, Primary Examiner. SIMON BRQDER, Examiner. 

1. AN ORTHOPEDIC INLAY FOR FOOTWEAR COMPRISING: A BASE HAVING A TOP SURFACE CONTOURED IN KEEPING WITH THE PLANAR SURFACE OF A NORMAL FOOT, AND A LAYER OF SUBSTANTIAL THICKNESS OF THERMOPLASTIC FOAM CUSHIONING MATERIAL HAVING 70% TO 100% GAS-FILLED CLOSED CELLS THROUGHOUT AND AN OUTER IMPERVIOUS SKIN, SAID LAYER CONFORMING UNDER FOOT PRESSURE TO THE SURFACE OF A FOOT AND BEING POSSESSED OF A LOW RECOVERY FACTOR OF LESS THAN 70% IN A TWO-HOUR INTERVAL AFTER REMOVAL OF FOOT PRESSURE. 